Overheat thermostat High

Alpha Overheat thermostat Fault Code

Also written as OVERHEATTHERMOSTAT — same fault.

The Alpha Overheat thermostat fault code means: your boiler has detected that it is getting too hot and has automatically switched itself off to prevent any damage.. It appears on 1 Alpha model in our database.

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description: Overheat thermostat has operated - press white reset button to reset
Typical repair cost £120-220 (including labour)

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Alpha models that show the Overheat thermostat fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Alpha Overheat thermostat fault code information on this page is sourced and cross-checked against the official Alpha service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026